1. Field of the Invention
The present invention relates to an ultraviolet irradiation system and a water quality monitoring instrument used in water treatment facilities for industrial water, for water purification processes putting great importance on securing water quality in terms of hygiene, and for the like. More particularly, the present invention relates to an ultraviolet irradiation system and a water quality monitoring instrument for optimizing an ultraviolet irradiation level by controlling the ultraviolet irradiation level while detecting water quality of water to be treated by using a fluorescence analysis to optimize the ultraviolet irradiation level.
2. Background Art
In facilities using river surface water as raw water, such as water treatment facilities, it is important to know beforehand a proportion of sewage mixed in river raw water for controlling treatment processes. Particularly, many water purification plants near a large city use the river surface water as the raw water. Thus, ammoniac nitrogen resulting from the sewage or chlorine-resistant pathogenic microorganisms contained in drainage from livestock farms located in an upstream region of a river cause a problem in the control of chlorination.
Particularly, in the treatment of the ammoniac nitrogen, it is required to install a chlorine demand meter which calculates a required amount of chlorine based on a residual chlorine amount after a sample is directly added with chlorine. Moreover, in the control by the residual chlorine and the treatment of chlorine-resistant pathogenic microorganisms, it is required to set the turbidity (specified by the Japanese Industrial Standards) of the treated water to 0.1 or less by controlling the accuracy in filtration (see Japanese Patent Application Publication Nos. 2003-260474 and 2003-90798).